利用泰勒公式,证明级数收敛,而级数发散.

A . 必在x=-3处发散 B . 必在x=2处收敛 C . 必在｜x｜>3时发散 D . 其收敛区间为[-2，3）

已知级数<img src='https://img2.soutiyun.com/ask/2020-12-21/977433142323243.png' />收敛，且u_n＞0，证明级数<img src='https://img2.soutiyun.com/ask/2020-12-21/977433151986795.png' />也收敛.

为什么说Abel定理是研究幂级数收敛性的一个基本定理？设有幂级数<img src='https://img2.soutiyun.com/ask/2020-12-22/9774786146116.png' />它在x=0处收敛,在x=3处发散,这可能吗？

讨论级数<img src='https://img2.soutiyun.com/ask/2020-12-17/9770605337287.png' />在哪些x处收敛？在哪些x处发散？

级数<img src='https://img2.soutiyun.com/ask/2020-12-11/976570396904071.png' />=(). A.发散 B.收敛于-a C.收敛于1 D.收敛于1-a

设幂级数<img src='https://img2.soutiyun.com/ask/2020-11-02/973183367447765.png' />处收敛,则此级数在x=2处() A.条件收敛 B.绝对收敛 C.发散 D.收敛性不能确定

设<img src='https://img2.soutiyun.com/ask/2020-11-02/973182947687756.png' />为收敛的正项级数,证明<img src='https://img2.soutiyun.com/ask/2020-11-02/973182957364309.png' />绝对收敛.

5．设幂级数<img src='https://img2.soutiyun.com/latex/latex.action' />的收敛半径为R(0＜R＜+∞)，则当______时，该幂级数绝对收敛；当______时，该幂级数发散。

证明：若<img src='https://img2.soutiyun.com/ask/2021-01-14/979479445751123.jpg' />都绝对收敛，则级数<img src='https://img2.soutiyun.com/ask/2021-01-14/979479456785754.jpg' />也绝对收敛。

证明:级数<img src='https://img2.soutiyun.com/ask/2021-01-05/97872007433638.png' />在[0,1]上绝对并一致收敛,但由其各项绝对值组成的级数在[0,1]上却不一致收敛.

设<img src='https://img2.soutiyun.com/ask/2020-12-14/976812927934874.png' />且<img src='https://img2.soutiyun.com/ask/2020-12-14/976812935497307.png' />收敛,则对于任意正数p,级数<img src='https://img2.soutiyun.com/ask/2020-12-14/976812944562825.png' />(). A.绝对收敛 B.条件收敛 C.发散 D.敛散性与p有关

证明:级数<img src='https://img2.soutiyun.com/ask/2020-12-22/977478451818289.png' />上一致收敛。

证明:将收敛级数<img src='https://img2.soutiyun.com/ask/2020-11-13/974114290584811.jpg' />相邻的奇偶项交换位置得到的新级数也收敛,且和不变.

设级数<img src='https://img2.soutiyun.com/ask/2021-01-14/979473223462229.jpg' />的绝对值级数<img src='https://img2.soutiyun.com/ask/2021-01-14/979473238100066.jpg' />发散，且其发散的结论是由比式判别法或根式判别法得到的，即我们有<img src='https://img2.soutiyun.com/ask/2021-01-14/979473272654042.jpg' />证明级数<img src='https://img2.soutiyun.com/ask/2021-01-14/979473324430004.jpg' />一定发散。

对于级数习<img src='https://img2.soutiyun.com/ask/2020-12-07/976201851181314.png' />下列结论中正确的是(). A.a＞1时,级数收敛 B.a＜1时,级数发散 C.a=1时,级数收敛 D.a=1时,级数发散

若<img src='https://img2.soutiyun.com/ask/2020-12-14/976827987925256.png' />绝对收敛，证明下列级数也绝对收敛: <img src='https://img2.soutiyun.com/ask/2020-12-14/976827980220816.png' />

对于一般项级数，由<img src='https://img2.soutiyun.com/ask/2021-01-14/979473354652732.jpg' />收敛，能证明<img src='https://img2.soutiyun.com/ask/2021-01-14/979473368087501.jpg' />收敛吗？为什么？

已知级数<img src='https://img2.soutiyun.com/ask/2021-01-20/9799846556874.png' />收敛，证明<img src='https://img2.soutiyun.com/ask/2021-01-20/979984676783606.png' />绝对收敛。

证明:若级数<img src='https://img2.soutiyun.com/ask/2020-11-13/974117042967238.jpg' />绝对收敛,则函数项级数 <img src='https://img2.soutiyun.com/ask/2020-11-13/974117058462124.png' /> 在R一致收敛.

证明:级数<img src='https://img2.soutiyun.com/ask/2021-01-05/978713333775842.png' />收敛.

证明级数<img src='https://img2.soutiyun.com/ask/2020-12-14/976814819355057.jpg' />在收敛圆内一致收敛。

幂级数<img src='https://img2.soutiyun.com/ask/2020-12-14/976814121928167.jpg' />在()绝对收敛，在()发散。

<img src='https://img2.soutiyun.com/ask/2020-12-22/977477173109151.png' />

此题为判断题(对，错)。